<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
for (var j=0; j<=6; j++){
    for(var i=0;i<=j;i++){
        document.write("*");
    }
    document.write("<br>")
}
</script>
</body>
</html>